Centrifuge having automatic means for controlling peripheral openings



Dec. 8, 1964 L. H. STONE 3,160,589

CENTRIFUGE HAVING AUTOMATIC MEANS FOR CONTROLLING PERIPHERAL OPENINGS 2Sheets-Sheet 1 Filed March 4, 1965 /lOO Currenf Source INVENTOR.

LAWRENCE STONE Sensmg SwiTch ATTOR NEY Solenoid Valve L. H. STONE3,160,589 CENTRIFUGE HAVING AUTOMATIC MEANS FOR Dec. 8, 1964 CONTROLLINGPERIPHERAL OPENINGS 2 Sheets-Sheet 2 Filed March 4, 1963 INVENTOR.

LAWRENCE H. STONE ATTORNEY United States Patent CENTRIFUGE HAVENGAUTQMATIC MEANS FGR QONTROLLING PERHPHERAL GRENH'JGS Lawrence H. Stone,Pararnus, Ni, assignor to Pennsalt Chemicals Corporation, a corporationct Pennsylvania Filed Mar. 4, 15. 63, Ser. No. 262,489 6 Claims. (Ul.233-) This invention relates to centrifuges. More specifically thisinvention relates to a centrifuge having improved means for controllingperipheral openings to discharge solids or other heavy components.

In the prior art it is well known to provide a centrifuge rotor withperipheral openings usually in the form of open nozzles for the purposeof discharging solids. Also well known are rotors having openingscontrolled by valves either manually operated through a control fluid orautomatically operated upon accumulation of solids to a preset level. Anexample of the latter type of rotor is disclosed in the US. Patent2,286,355 which issued June 16, 1942 on an application filed by HaroldC. Fitzsimmons.

The present invention is an improvement on the device of theabove-mentioned Fitzsimrnons patent in that it provides means by whichthe open-close cycle of a peripheral valve may be adjusted withoutstopping the centrifuge. Hence by the apparatus embodying the invention,the extent to which solids are permitted to accumulate for instance maybe controlled While the machine is in operation.

Other features of the invention will be apparent upon reference to thedrawings in the following description disclosing a preferred form of theinvention.

FIGURE 1 is a fragmentary sectional View, partly in elevation, of anapparatus embodying the invention;

FIGURE 2 is a schematic circuit diagram of an apparatus embodying theinvention;

FIGURE 3 is an enlarged fragmentary sectional View of the sensing switchmeans of an embodiment of the invention;

FIGURE 4 is an enlarged fragmentary sectional view taken on the line 4-4of FIGURE 1; and

FIGURE 5 is a fragmentary sectional view taken on the line 5-5 of FIGURE4.

Briefly, the invention is a centrifuge having at least one valvedperipheral opening for occasional solids discharge, the valve having anelectric control actuated by solids sensing means in the centrifuge.

Referring more specifically to the drawings, a centrifuge rotorembodying the invention is designated it} in FIG- URE 1. It comprises arotor shell 12 mounted on a power spindle 14 which is driven by meansnot shown.

Disposed on a shoulder adjacent the upper end of the rotor shell 12 isthe rotor cover 16 which is held down against the shoulder by a threadedring element 18. The rotor shell 12 has discharge openings 20. A centertube 22 sits on a shoulder formed on the inner portion of the rotorshell 12 and features an outwardly and upwardly flaring skirt 24 formedwith a feed opening 26. A stack 28 of frustc-conical discs rests on theskirt 24 and is held compressively between the skirt and the rotor cover16. The feed pipe 3% delivers feed into the center tube.

The disc stack 28 is superposed by a conventional dividing cone havingupward spacers to provide therebetween a passage 32 for heavy liquiddischarge over a weir 34. The dividing cone is provided with alongitudinal tubular extension 36 for conducting light liquid dischargein the conventional manner.

Mounted for reciprocation between the rotor shell 12 and the skirt 24 isthe valve element 38 which is formed with a leak opening 39. As isconventional the valve element is biased upwardly preferably by thepresence of liquid in the chamber 49 which may be supplied throughPatented Dec. 8, 1964 ice tube 42, pocket 44 in the rotor shell 12 andthin-bored passage 46. Drain 4S vents excess.

The valve element 38 may be moved downward to provide an opening belowcover 1o by a flow of liquid into the chamber 5i; through tube 42,pocket 44 and passage 52. Downward movement of valve element 38 may beeifected when the liquid pressure force against the upward side of theelement exceeds that on the lower side.

The cycle of flow of control liquid through the tube 42 is initiated bythe electric switch 54 mounted on the inside of the cover 16 and theskirt 24. Leads 56 from the switch are connected respectively to sliprings 58 mounted on spacers 69 (FIGS. 4 and 5). The spacers permitpassage of the heavy liquid discharge between the cover 16 and therings. The rings 58 are engaged respec tively by contacts 62 mounted ona stationary bracket which may be supported on the under side of thelight liquid collector as shown.

Referring to FIGURE 3, a fluid motor 64 operates to move the switch. Itcomprises a housing which consists of an end portion 66 and a baseportion as to which the end portion 66 is secured. The base portion 68has an annular extension 7% which lies adjacent but is suitably spacedby space 71 from the juncture of the walls of cover 16 and shrt 24. Apiston 72 which is the moving member of the fluid motor is mounted forreciprocation in end portion 66 and has a stem '74 which extendstherethrough.

The housing base 68 is provided with a lateral extension 76 throughwhich liquid is passed from the main body of the rotor for actuating thefluid motor.

A bore 78 in extension 76 communicates with the space 71 through thepassage provided by the annular flange 79. The bore 78 is in turnconnected with a conduit 82 which extends downwardly and inwardly aroundthe lower end of the stack 28 of discs and into an opening in the skirt24. The inner end of the conduit 82 is connected to a member 84 whichhas a bore 86 communicating with the conduit 82 and also a channel 38communicating with the inner end of bore 36. A second bore extendsoutwardly from the channel 88 and is connected to a second conduit 92which is connected with a bore 94 in the lateral extension 76 of thehousing base 63.

The bore 94 communicates with the space as between the inside portion 64of the housing and the outer surface of the piston 72. The inner surfaceof the piston 72 communicates with the space 71 of the rotor through thehollow interior of the guide 98 which is a stationary member along whichthe piston reciprocates, rubber rings acting as a seal. The space as isalso in communication to the outside of the rotor through a leak passage1%.

Mounted over the end portion 65 is the switch cap 192 which carries acontact button 134- and a spring contact 106 to which the leads 56 areattached, respectively.

The contact button 134 and the spring contact 1&6 comprise theelectrical elements of the sensing switch shown in circuit (FIG. 2) witha timer and solenoid valve in the control liquid, such as line 52. Underthe arrangement shown after the switch has been closed for a perioddepending on the setting of the timer the solenoid valve will be openedto effect the opening of the valve element 38.

The operation will be understood by further reference to FlGURE 3. Asthe centrifuge it; is brought up to speed the piston 72 is thrownoutward under centrifugal force. As the rotor is filled with feedmixture, some will pass inward through the opening in extension 76 andin through the guide 98 to urge the piston inwardly. Liquid will alsopass inward through passage '78, conduit 82 to channel 88 and outwardthrough conduit 92, passage 94 to chamber 96 to urge the piston outward.The force on the opposite sides of the piston '72 being equal,

the weight of the piston urges it to its outward position shown. Whensolids accumulate to cover the opening between the annular extension 70and passage 78 travel of liquid through passages 82 and 92 to chamber 96ceases and the chamber is evacuated as its liquid drains through passage100. This leaves liquid acting on the outer face of piston 72 againstthe weight of the piston only and the result is the inward movement ofthe piston closing the contacts 104 and 106. This, through the circuitshown in FIGURE 2, commences operation of the timer and eventually opensthe solenoid valve to lower element 38 and permits solids to escapethrough the passage 20. When the evacuation of solids from the areaaround the opening between the annular extension 70 and passage 78 oncemore permits passage of liquid to chamber 96, the piston will moveoutward, opening the contacts to close the solenoid valve. The liquiddraining through the passage 39 removes the downward force on element 33which raises to close the rotor again.

It should be understood that the above operation including the closingof the peripheral opening after the solids are discharged is based onthe mode of use in which the feed rate to the centrifuge is greater thanthe rate of discharge through the openings 20. In the situation in whichsuch discharge exceeds the feed rate, the level of liquid in the bowlwill move outward when the openings 20 are opened and after solidsdischarge there will be no pressure available to drive liquid in throughpassage 78 to channel 88 and ultimately to chamber 96 to move the piston72 outward to open the contacts as described above. Instead the pistonwill remain in its inward position and the contacts closed until theliquid level moves outward of the outer face of piston 72. To assurecontrol in such a situation additional adjustable timing means may beprovided, for instance to break the circuit shown in FIGURE 2 after theelapse of a preset time, and keep the circuit open until the liquid inthe bowl has returned to its inward level, thereby opening contacts 104,106.

From the above description it will be apparent to one skilled in the artthat Ihave developed means for controlling the discharge of solids froma centrifuge rotor in a way which may be adjusted while the rotor is inoperation to control the residence time of solids in the bowl and hencethe degree of compaction of solids. This improvement will be of benefitto those, for instance, in the vegetable oil industry wherein inWinterizing it is essential that the stearine solids remain in the bowlsufficiently long to force out entrained oil portions, but not so longthat they affect the clarity of the liquid discharge.

Variations in structure are possible. For instance, control of theamount of time that the rotor remains open may be achieved by means fordelaying-the closing of the solenoid valve. Further, if desired andpermitted, one of the contacts 104 and 106 may be grounded to the frameof the machine and one of the leads 56 and rings may be dispensed with,the machine itself acting as a conductor. Additionally skirt 24 may bedispensed with and the valve element 38 may constitute the bottom wallof the bowl biased downward by liquid in the bowl. In such anarrangement the chamber 40 may be pressurized with control liquid asknown in the art to keep the element up against its seat on cover 16closing the bowl until an opening is desired. These and other variationsare deemed to be within the competence of one skilled in the art.

Therefore, having particularly described my invention, it is to beunderstood that the description is by way of illustration and thatchanges, omissions, additions, substitutions and/ or other modificationsmay be made without departing from the spirit thereof. Accordingly, itis intended that the patent shall cover by suitable expression in theclaims the various features of patentable novelty that reside in theinvention.

I claim:

1. In combination,

(a) a centrifuge having a centrifuging zone having at least oneperipheral opening for the discharge of solids from said centrifugingzone,

(b) an hydraulically operated valve element disposed in the centrifugeand controlling said peripheral opening, the valve element having anhydraulic power chamber,

(c) conduit means for supplying a control fluid to said power chamber todrive the valve element in one direction,

(d) electrically actuatable valve means in said conduit means to controlthe flow of control fluid to the power chamber,

(e) means in the centrifuge biasing the valve element in the oppositedirection,

(f) fluid motor means in said centrifuging zone,

(g) a piston constituting part of the fluid motor means and having twosides, one side being exposed to the inside of the motor means, and theother side being exposed to the centrifuging zone,

(1:) passage means in said centrifuge zone having an inlet and connectedto the inside of the fluid motor,

(1) outlet means from the inside of the fluid motor to the outside ofthe centrifuging zone, and

(j) electric switch means in said centrifuging zone adjacent said pistonand adapted to be operated thereby, said switch means being electricallyconnected to said electrically actuatable valve means to corn trol it,

whereby when solids accumulate in said zone to block said inlet aportion of the liquid contents of said fluid motor will drain throughthe outlet means to reduce pressure in the motor so that the pistonmoves to operate the switch means which in turn operates theelectrically actuatable valve means controlling flow of control fluid tothe power chamber to open the valve element controlling the peripheralopening to permit solids to discharge therethrough.

2. The combination of claim 1 wherein adjustable time delay means are incircuit with the electric switch means to delay opening of the valveelement for a preset period after the electric switch means is operatedby said movement of the piston.

3. The combination of claim 1 wherein the electric switch means iselectrically connected to said electrically actuatable valve meansthrough at least one slip ring mounted on said centrifuge.

4. The combination of claim 1 wherein the valve element comprises anannular element positioned about the axis of the centrifuge and adaptedto move in axial directions.

5 The combination of claim 1 wherein adjustable electric timing meansare provided in circuit with the electric switch means to assuresubsequent closing of the valve element.

6. The combination of claim 1 wherein said passage means includesportions extending in directions both inward of the centrifuging zoneand outward of the zone.

References Cited by the Examiner UNITED STATES PATENTS 802,473 10/05Raasloft 233-20 X 1,375,506 4/21 Gray 233-20 X 2,113,175 4/38 Elrod233-20 2,286,355 6/42 Fitzsimmons 233-46 X 2,378,778 6/45 Lindglen .eta1. 233-20 2,501,179 3/50 Komline 233-20 2,723,799 11/55 Sharples 233-202,820,589 1/58 Fitzsimmons 233-20 2,955,754 10/60 Nyrop 233-20 (Qtherreferences on following page) FOREIGN PATENTS Great Britain. GreatBritain. Germany. Netherlands.

6 OTHER REFERENCES GEORGE D. MITCHELL, Primary Examiner. ROBERT F.BURNETT, Examiner.

1. IN COMBINATION, (A) A CENTRIFUGE HAVING A CENTRIFUGING ZONE HAVING ATLEAST ONE PERIPHERAL OPENING FOR THE DISCHARGE OF SOLIDS FROM SAIDCENTRIFUGING ZONE, (B) AN HYDRAULICALLY OPERATED VALVE ELEMENT DISPOSEDIN THE CENTRIFUGE AND CONTROLLING SAID PERIPHERAL OPENING, THE VALVEELEMENT HAVING AN HYDRAULIC POWER CHAMBER, (C) CONDUIT MEANS FORSUPPLYING A CONTROL FLUID TO SAID POWER CHAMGER TO DRIVE THE VALVEELEMENT IN ONE DIRECTION, (D) ELECTRICALLY ACTUATABLE VALVE MEANS INSAID CONDUIT MEANS TO CONTROL THE FLOW OF CONTROL FLUID TO THE POWERCHAMBER, (E) MEANS IN THE CENTRIFUGE BIASING THE VALVE ELEMENT IN THEOPPOSITE DIRECTION, (F) FLUID MOTOR MEANS IN SAID CENTRIFUGING ZONE, (G)A PISTON CONSTITUTING PART OF THE FLUID MOTOR MEANS AND HAVING TWOSIDES, ONE SIDE BEING EXPOSED TO THE INSIDE OF THE MOTOR MEANS, AND THEOTHER SIDE BEING EXPOSED TO THE CENTRIFUGING ZONE, (H) PASSAGE MEANS INSAID CENTRIFUGE ZONE HAVING AN INLET AND CONNECTED TO THE INSIDE OF THEFLUID MOTOR, (I) OUTLET MEANS FROM THE INSIDE OF THE FLUID MOTOR TO THEOUTSIDE OF THE CENTRIFUGING ZONE, AND (J) ELECTRIC SWITCH MEANS IN SAIDCENTRIFUGING ZONE ADJACENT SAID PISTON AND ADAPTED TO BE OPERATEDTHEREBY, SAID SWITCH MEANS BEING ELECTRICALLY CONNECTED TO SAIDELECTRICALLY ACTUATABLE VALVE MEANS TO CONTROL IT, WHEREBY WHEN SOLIDSACCUMULATE IN SAID ZONE TO BLOCK SAID INLET A PORTION OF THE LIQUIDCONTENTS OF SAID FLUID MOTOR WILL DRAIN THROUGH THE OUTLET MEANS TOREDUCE PRESSURE IN THE MOTOR SO THAT THE PISTON MOVES TO OPERATE THESWITCH MEANS WHICH IN TURN OPERATES THE ELECTRICALLY ACTUATABLE VALVEMEANS CONTROLLING FLOW OF CONTROL FLUID TO THE POWER CHAMBER TO OPEN THEVALVE ELEMENT CONTROLLING THE PERIPHERAL OPENING TO PERMIT SOLIDS TODISCHARGE THERETHROUGH.